Plastic water bottles are made of polyethylene terephthalate (PET). That’s a fancy term for “oil-based stuff.” Heat makes plastic release chemicals. Antimony, a heavy metal, can seep into the water after just a few hours in the sun. The longer it sits, the more you sip—literally.
Don’t panic, though. The amount is tiny. You’d need to drink dozens of sun-baked bottles to feel sick. But still? Not exactly what you signed up for on a sunny picnic.
The Weirdest Fact: Glass Bottles Are Worse
Thinking of switching to glass? Big mistake. Glass heats up faster than plastic. It acts like a magnifying glass on your drink. In direct sun, a glass bottle can hit 180°F (82°C) in under an hour. That’s hot enough to burn your lips—and definitely hot enough to leach chemicals from any plastic lid.
Stainless steel? Now you’re talking. Metal bottles reflect heat. They keep water cool for hours, even in a blazing car. Plus, no leaching. That’s a win.
